It's the banana I'd say. We stopped giving it to our DD because it constipated her. She started rushing up much worse than usual after I went back to work and she was being cared for by her grandparents. We thought it was the cat at my MILs but turns out my dad had been giving her banana and not telling us. (I had told him not to give her any food outside of what I make her as she has a few allergies)
we worked it out once her skin cleared up after some antibiotic cream when my DH gave her a bit of banana as a test and within 2 hours her rashes were back.
this is how bad it got before we made my dad stop with the banana. .... So I'd stay away from banana.